@taiyo Right. Mixi was used for organizing some, such as against the PSE laws. But I agree that things in Mixi weren't that "viral" compared to the next generation of social media such as Twitter.
https://www.jcp.or.jp/akahata/aik4/2006-12-04/2006120410_01_0.html
https://mixi.jp/view_community.pl?id=620306
Then Mastodon is post-Twitter and seems designed to be less viral, such as not having quote-retweet. Search is, I'm not sure. It is inconvenient, but it may not be a blocker regarding mainstream adaption. Instgram/TikTok are fine w/ just having hashtags.